Zeroizing mechanism



March 2, 1943. W` B, LANG 2,3242

ZEROIZ ING MECHANISM Filed Sept. 5, 1940 Patented Mar. 2, 1943 UNITED STATES PATENT oFFlcE ZEBOIZING MECHANISM Walter B. Lang, Washington, D. C. Application September 5, 1940, Serial No. 355,468 1 Claim. (Cl. 23S-144) (Granted under the act of March 3, 1883, as

amended 'April 30, 1928; 370 0. G. 757) The invention described herein may be manufactured and used by or for the Government of the United States for governmental purposes without the payment to me of any royalty thereis mounted a switch box 1. The said contacts 3, 3A and 3B are connected by wires 6, 6A and 6B to this switch box while a plurality of independent counters or odometers are arranged on in accordance with the provisions of the act 5 in the case 4 under the switch box. By any of April 30, 1928 (Ch. 460, 45 Stat. L. 467). suitable arrangement any one of the contacts 3. This invention relates to the class of devices 3A and 3B may be connected to any of the ingenerally known as odometers and has for its dependent counters or odometers 5 arranged object to provide a mechanism for measuring within the case 4 for ready removal therefrom. and indicating a lseries of consecutive distances 10 In circuit between the counters 5 and the batwhen the device is applied to an automobile. tery 9 is an automatic cut-out relay 8 tc open The invention more particularly consists in the circuit in the event the vehicle is stopped the odometer-reset mechanism so arranged in with one of the said contacts 3, 3A or 3B in conassociation with the counter wheels that the tact with one of the said commutator segments. counter wheels are rotated and reset to their zero While the apparatus just described is considpositions under the influence of vibration, gravered to be preferable, any other construction of ity and magnetism, which reset mechanism may commutator and any other arrangement of the or may not be used in connection with the parapparatus shown in Fig. 1, and as just decribed ticular commutator assembly hereinafter demay be employed. scribed, but, in connection with which, it is Referring now to the reset mechanism which herein disclosed as being particularly adapted forms the subject matter of the invention, I0 for use. indicates the rst or units counter wheel of the The invention further consists of certain comodometer. On the periphery of this counter binations of parts, all of which will first be fully wheel appear the numerals 0 to 9, as is usual described and afterwards specifically pointed out in odometer practicewhile the balance of the in the appended claim. counter wheels are similarly supplied with nu- Referring to the accompanying drawing: merals 0 to 9 and are face to face on a common Fig. 1 is a diagrammatic illustration of a preshaft 29` in regular odometer fashion. Also the ferred form of the measuring device and shows usual odometer mechanism is employed for coma commutator and distributor and also a counter municating the movement of one counter wheel box, automatic relay and battery. to the next adjacent counter wheel.

Fig.,2 is a diagrammatic illustration of the In Fig. 2 the movement of the rst or units odometer or counter-reset mechanism. counter wheel I0 is communicated to the bal- With reference to the form of commutator ance of the usual counter wheels by a pinion preferred for use with the odometer which congear I6 which is normally in mesh with the large stitutes the subject matter of this invention, it spur gear Wheel 3| on the outer face of the first will be seen from Fig. 1, that the commutator I or unit counter wheel I0. hasathree course track, upon which is arranged An electro-magnet I3 is provided for each a plurality of grounded segments 2, 2A, 2B and odometer 5 which electro-magnet may be con- 2C, each of a` diierent length. This commuta- 40 nected in circuit with any one of the commutator is positioned within the brake-drum houstor contacts 3, 3A or 3B through the switch box ing of the wheel of an automobile and rotates 1, so that when the circuit is closed by engagewith the wheel. On the brake-drum housing of ment of one of the commutator segments 2, 2A, the wheel, three electrically independent roller 2B or 2C with one of the said contacts 3, 3A or or brush contacts 3, 3A and 3B are arranged so 45 3B, the electro-magnet I3 is energized. as to ride on the courses on the face of the com- In proper relation to the electro-magnet I3, mutator I, so that the innermost contact 3B enthere is arranged a pivoted armature I2, which gages all four of the said segments at each revoin turn is pivotally connected to a pawl II which lution of the commutator; the intermediateconcoacts with a ratchet Wheel 26 centrally arranged tact 3A engages two of the said segments 2B 50 on the face of the spur gear wheel 3l of the and 2, while the outer-most contact 3 engages counter wheel I0. Each time the circuit is closed only the one segment 2, at each revolution of by the commutator I, and one of its associated the commutator I. contacts 3, 3A or 3B, and the electro-magnet I3 Suitably located in the vehicles and readily thereby energized, the pivoted armature I2, accessible to the operator is a case 4 upon which 55 which is normally held away from the said electro-magnet, by the spring I2A, is biased toward the electro-magnet. This movement of the pivoted armature I2, moves the pawl II and rotates the ratchet wheel 28 the distance equal to one tooth thereof. The counter wheel I rotates with the ratchet wheel 26, and this rotatable movement is communicated to the small pinion I6 through the medium of the large spur gear 3| in the manner as will be clearly understood from Fig. 2. If the electro-magnet I3 is in circuit with the outer-most contact 3 of the commutator assembly, the electro-magnet I3 will be energized only once for each revolution of the commutator and vehicle wheel to which it is attached. If the electro-magnet I3 is in circuit with the intermediate contact 3A,

the circuit will be closed twice, that is to say, by the two commutator segments 2 and 2B for each revolution of the commutator, while if the electro-magnet I3 is in circuit with the innermost contact 3B, the circuit will be closed four times, that is to say by all four of the commutator segments 2, 2A, 2B and 2C for each revolution of the commutator I. In this case, the electro-magnet-is energized four times and the ratchet wheel 26 is rotated the distance equal to four teeth thereof for each revolution of the commutator I.

In order to prevent casual rotation of the ratchet wheel 26 during the time that the actuating pawl I| is being returned back to its normal position under the inuence of the spring I2A acting on the pivoted armature I2, a detent I4 pivoted at |4A is biased by the spring I5 into engagement with the ratchet wheel 26. This detent I4, While permitting free rotation of the ratchet wheel 26 under the inuence of the pivoted armature and its pawl II, in a clockwise direction, effectually locks the ratchet wheel 26 against anti-clock-wise rotation.

With reference to the counter re-setting mechanism, it is necessary that all of the counter wheels be relieved of all locking or restraining inuence, in order to permit each of the counter wheels to be returned to their zero positions. To accomplish this I provide a manually operable vertical plunger 25 normally held in raised position by a spring 25. Pivoted adjacent said plunger and in the path of movement of an extension 24A on the plunger 24, is a pivoted detent 21, which, upon downward movement of the plunger 24 is engaged by said extension 24A and is rocked into engagement with the paw] II and raises the same out of engagement with its ratchet wheel 26. Simultaneously an extension 24B on the plunger 24 engages the pivoted detent I4 and depresses the same out of engagement with the ratchet wheel 26. The same downward movement of the plunger 24 causes an extension 24C thereon to engage the arm 28 in which 'the shaft of the pinion I6 is mounted. This arm 28 is pivoted at 28A and normally maintains the pinion I6 in mesh with the large spur gear wheel 3| under spring influence, and

being arranged in the path of movement of the said extension 24C on the plunger 24, said arm is depressed thereby and the pinion I6 is moved out of mesh with the large spur gear 3| and into mesh in a short toothed rack 23 located under the pinion I6. This movement of the pinion I6 and its shaft out of its normal operative meshed position likewise disengages the balance of the counter wheels from their motivating connections. and disengages all of the counter wheels from all restraining iniluence and.leaves them free to be rotated on their common shaft 29.

Each ot the counter wheels I0 is provided on or near the periphery thereot with an iron counter weight I1, while the number wheels themselves are of non-magnetic material. This iron counter weight on each number wheel I0 is suiliciently heavy to tend to cause each wheel to rotate until the counter Weight Il approaches its lowermost point, as shown in Fig. 2, and.ls disposed on each number wheel I@ in such position that when all the counter weights`are at their lowermost position, as shown in Fig. 2, the reading on each wheel will show zero.

In order to accomplish this zero re-setting oi.' the counter wheels, they are subjected to a simultaneous vibrating, gravity and magnetic influence as Will be now described.

Pivoted at 30 adjacent the counter wheels I3 is an electro-magnet I9 having its free end enlarged and upturned for magnetic cooperation with a stationary plate I8 arranged as close as may be to the peripheries of the counter wheels I 0 and extending. directly under center of each wheel. Arranged on the electro-magnet I9 is a contact piece 22A which is normally in contact with a similar contact piece 26 in circuit with the electro-magnet winding 2, it being understood that the weight of the electro-magnet IS normally maintains the pieces 2@ and 2BA in electrical contact. Referring now to the pivoted pinion-carrying arm 28, it will be seen that it is also an electrical conductor, in that it is located in the circuit which energizes the electro-magnet I 9. It will be also seen that this arm 28 is provided with a contact piece 22A arranged for electrical cooperation with an adjacent Contact piece 22 in circuit with the electro-magnet I9.

The operation of this vibrator mechanism is as follows:

The contact pieces 20 and 23A being normally in electrical contact under the influence of the weight of the electro-magnet I9, downward movement of the plunger 2d depresses the pinion-carrying arm 23 and brings the contact piece 22A thereon in contact with its associated contact piece 20. This closes the circuit and the electromagnet I9 being thereby energized, it swings upwardly on its pivot 30 into striking contact with the stationary plate I3. This upward movement of the electro-magnet I9 breaks the electrical contact between the contact pieces 2i) and 22A and opens the circuit which de-energizes the electro-magnet and causes the same to drop down of its own weight to again bring the contact pieces 2|! and 26A together. This again closes the circuit, energizing the electro-magnet I9 and causes it to again be drawn into striking engagement with the stationary plate I8. Thus a rapid vibrating motion is imparted to the electro-magnet I9 which results in its rapidly striking the stationary plate I8 suicient to set the entire counter wheel assembly in rapid vibration. This vibratory action `is continued as long as the plunger 24 is maintained in a depressed position, and ceases as soon as said plunger is permitted to assume its normal raised position. The eiect of this rapid vibration impressed upon the counter wheel assembly is to jar or vibrate the counterv weights I1 into theiriowermost position and directly above the stationary plate I8. Assisting in bringing the iron counter weights into and maintaining them in their lowermost position is the magnetic attraction exerted thereon by the electro-magnet I9 during its period of vibration as will be at once apparent. As soon as all of the counter wheels I0 have been rotated into zero position by vibration and magnetic iniluence as just described, the plunger 24 is released into its normal position which movement permits the `several elements affected by the depression of the plunger 24 to again assume their normal operative positions to lock the counter wheels in zero position and put the device in condition for further service.

A It will be seen that the vibration of the device jars the counterweights I'I to overcome any inertia which may have the eiect of retarding the influence of gravity on them and facilitates the movement of the counterweights under the iniluence of gravity to positions at or near the lowermost positions directly under the central axes of the wheels. As these counterweights II approach their lowermost positions, their tendencies to rotate the wheels gradually decrease, so that under their influence alone, the wheels may Ystop short of their actual zero positions, or may pass beyond their actual zero positions. As

soon, therefore, as these counterweights I'I, which are of magnetic material reach positions over or closely adjacent the plate I8, they come within the magnetic eld set up in the plate I8 each time the electro-magnet I9 strikes the plate I8 during its vibratory action, and are thus caused to be moved and come to rest at their lowermost positions which are closest to the plate I8, and which are the zero positions of the wheels.

Since the introduction of the front Wheel brake, no automobile so equipped is free running at all times, although it may be considered to be suiciently close for most reconnaissance purposes. If great accuracy, however, is required, a fifth wheel for mounting the commut'ator may be attached.

.With the 28 inch tire having a circumference of approximately 88 inches, now in common use, very small measurements, approximately two feet, can be made by the commutator of Fig. 1 when making four contacts per revolution.

Having thus described the invention, I claim:

4A reset mechanism for a counterwheel including an electro-magnet and plate closely adjacent the counterwheel, the said plate being disposed directly under the center of the counterwheel, an iron counterweight near the periphery of the counterwheel and tending to rotate the wheel by gravity, and manually operable means for closing an electrical circuit to energize the electromagnet and cause the electro-magnet to strike the said plate to vibrate the counterwheel to assist the action of gravity on the counter-weight 

